Power mower safety mechanism

ABSTRACT

This disclosure relates to a rotary type of lawn mower having a skirted housing, a power motor mounted on the housing, a rotary grass cutting blade driven by the power motor, and a blade lifting assembly for selectively raising the rotary blade substantially against the underside of the housing.

United States Patent Sotak et al. Jan. 8, 1974 [54] POWER MOWER SAFETYMECHANISM 3,086,346 4/1963 Zimmermann. 56/ 17.1

[76] Inventors: John B. Sotak, 122 Church Rd.,

Irwin, Pa. 15642; Harold A. Williamson 5 59 Idlewood Rd PrimaryExammer-Lou1s G. Mancene Penn Allegheny Assistant Examiner-J. ESkOVItZCounty, Pa. 15235 [22] Filed: Dec. 23, 1971 3 [21] App]. No.: 211,385[57] ABSTRACT 52 vs. C] 56/l0.2, 56/1704 This disclosure relates to a ay yp of lawn mower 51 1m. (:1 A0.ld 53/00 having a Skirted housing, apower meter mounted on 58 Field of Search 56/102, 10.4, 12.1, thehousing, a rotary grass cutting blade driven y the 56/171 174 255 powermotor, and a blade lifting assembly for selectively raising the rotaryblade substantially against the References Cited underside of thehousing. I

UNITED STATES PATENTS I Wilgus 56/17.]

12 Claims, 5 Drawing Figures PATENTED 8 3. 7 83 .591

sum 2 OF 3 RAISE BLADE BEFORE. STORING AND STARTING.

INVENTORY f0/2n B. $06M and Ha od 4. VVZdL'a/nfoa.

1 POWER MOWER SAFETY MECHANISM Our invention relates to a power mowersafety mechanism, and more particularly to a mechanically operated bladelifting assembly for selectively raising the grass cutting blade of arotary type of power driven lawn mower.

The number of lawn mower accidents has reached alarming proportions andhas caused the industries trade group as well as the governmentalauthorities to pursue and to enact more stringent standards andregulations for alleviating this problem. Critics claim thatapproximately 150,000 persons are injured annually, and that of thisnumber about 90 percent of the lawn mower accidents are caused by rotarytypes of power mowers. One major cause of accidents occurs when anoperator inadvertently pulls the mower over his foot and causes severeinjury to himself. A similar injury is caused when an operator falls onan embankment or slides on the freshly cut wet grass so that his footslips under the lawn mower housing and the high speed rotary bladesevers his toes and foot. Numerous lawn mower operators are also injuredwhen they attempt to remove the clogged grass from underneath the lawnmower and inadvertently contact the high speed rotary blade with theirhands. Others are injured by attempting to remove stones, twigs, and thelike from under or near the skirted housing of the rotary mower. Inaddition, individuals are injured and property is damaged by flyingobjects hurled by the high speed rotating blade. For example, stones,nails, twigs, and other objects are projected by the rotary blade withbullet-like force. Thus, many severe injuries, such as lacerations andblindings, as well as several fatalities, are caused by objectspropelled by rotary power mowers.

A further shortcoming of many conventional rotary power mowers is thescalping of the lawn. That is, when the rotating blade contacts a highspot on the lawn, the surface grass and part of the root system arechopped off by the rotating blade.

In addition, unobserved objects, such as rocks, tree stumps and otherimpediments cause costly damage to the rotary mower by dulling andunbalancing the blade or by bending the drive shaft of the engine.

Further, both pull and winding recoil types of engines are usuallydifficult to start in tall grass due to the resistanceof the grass onthe cutting blade.

Accordingly, it is an object of our invention to provide a rotary powermower which is safer, better, and easier to operate.-

' Another object of our invention is to provide a saftey mechanism for arotary power mower wherein an operator may selectively raise and lowerthe cutting blade. A further object of our invention is to provide apower mower with a safety mechanism which is cooperatively related withthe skirted housing and the rotary cutting blade for selectivelychanging the distance between the underside of the skirted housing andthe rotating cutting blade.

Still another object of our invention is to provide a mechanicalarrangement cooperatively associated with a rotary blade of a powermower which allows the cutting blade to be moved adjacent the undersideof the skirted housing when desired. Still a further object of ourinvention is to provide a safety mechanism for a power mower whichreduces the chance of injury to the operator or to nearby individualsand which decreases the possibility of damage to surrounding property.

Yet another object of our invention is to provide a mechanical safetyarrangement for 'a rotary lawn mower which raises the cutting blade toallow for easier starting in high grassy areas.

Yet a further object of our invention is to provide a mechanicalarrangement for a power mower which results in the blade beingautomatically raised when it engages a high spot in the lawn.

Still yet another object of our invention is to provide a safetymechanism which quickly and positively lifts the rotary blade of a powermower to allow for easier.

and safer starting and to reduce the chance of injury to individuals andproperty during grass cutting operation.

Still yet another object of our invention is to provide a novel bladelifting assembly for a power rotary mower which is economical in cost,simple in construction, reliable in operation, durable in use, andefficient inservice.

Other objects and further features and advantages of our invention willbecome more fully evident from the following detailed description whenconsidered in connection with the accompanying drawings wherein:

FIG. 1 is a side elevational view, partly in section, of the powerdriven rotary lawn mower utilizing the safety mechanism embodying ourinvention.

FIG. 2 is a top plan sectional view of a rotary type of the lawn mowertaken along lines 11-11 of FIG. 1.

FIG. 3 is a rear elevational view of the power driven rotary lawn mowerof FIGS. 1 and 2.

FIG. 4 is an enlarged fragmentary perspective view, partly in section,of the wedge operated cam follower employed in practicing our invention.

FIG. 5 is a greatly enlarged sectional view of the blade lifting devicetaken along lines VV of FIG. 2.

Briefly, our invention relates to a safety mechanism for a rotary powermower having a skirted protective housing carrying a power motor fordriving a grass cutting blade. The safety mechanism includes a bladelifting device having a rotatable and axially movable spring biasedspindle which has an upper enlarged portion. The grass cutting blade issecured to the lower end of the movable spindle, and a cam groove isformed on the peripheral surface of the upper enlarged portion of themovable spindle. A spring: biased follower rod includes a conical rollerwhich is disposed on one end thereof. An actuating device includinga'slidable wedge member is coupled to the other end of the cam followerrod. An operating device including a depending kick flap and a resetfoot pedal is linked to the wedge member. When the dependingflap iscontacted by the foot ofan individual, the wedge member is moved to itsthin edge so that the springbiased cam follower rod moves the rollerinto engagement with the cam groove. The engagement of the roller withthe cam groove quickly raises the spindle and, in turn, lifts the grasscutting blade substantially against the underside of the skirtedhousing. The individual may return the grass cutting blade to its lowergrass cutting position simply by stepping of the reset foot pedal. Theforward movement of the foot pedal causes the wedge member to move toits thick edge so that the cam follower rod and, in tum, the roller arewithdrawn from the cam groove. The withdrawal of the cam roller allowsgravity and the force of the spindle spring tomove the grass cuttingblade to its lower grass cutting position.

Referring now to the drawings and in particular to FIGS. 1, 2 and 3,there is shown a rotary type of power driven lawn mower generallycharacterized by the reference numeral 1. The rotary mower 1 includes ametallic protective housing 2 having an upper flat portion 2a and aperipheral skirt 2b which completely encompass the housing with theexception of an open grassemitting chute 3. The underside of the housing2 is provided with an annular ring or rim 2c which has a diameterslightly larger than the length of the grass cutting blade and a depthslightly larger than the thickness of the blade, as will be describedhereinafter. Generally, the metallic housing is supported by four wheels4 which allow the lawn mower to be pushed or propelled along its routeof travel. A motor, such as a high speed gasoline engine 5, isconventionally employed to provide the necessary driving power forturning the rotary cutting blade 6. The engine 5 is generally located ontop of the housing 2 and is suitably bolted to the housing 2. In thepresent case, the engine 5 is flange mounted on an upstanding hollowcylindrical sleeve or tubulure 7 which is shown formed as an integralpart of the housing 2. Traditionally, the lawn mower 1 includes aguiding handle having a pair of depending arms 8, each of which issuitably secured to the back end of the housing 2. In the presentinstance, the lower ends of the arms 8 are pivotally connected toapertured lugs 9 by suitable fasteners, such as, bolts and nuts. Asshown, the rotating cutting blade 6 is securely fastened to the end of adrive shaft 10, such as by a case hardened bolt 12 and a pair ofoversized washers l3 and 14, or by some similar arrangement.

A blade lifting assembly or device takes the form of a simple machine,namely, a cam and follower arrangement which is housed within the hollowtubulure 7. In viewing FIG. 5, it will be noted the spindle or shaftincludes an upper enlarged portion 15 which is disposed within thehollow cylindrical sleeve or tubulure 7. The enlarged spindle portion 15includes a relatively deep centrally located splined bore 16 foraccommodating an engine output shaft 17 which extends through a bearingand seal (not characterized) located in the bottom of the engine 5. Theend of the output shaft 17 is also splined so that rotary movement isimparted to the shaft 10 and blade 6 when the engine is running. Asuitable bearing member 18 and seal 19 are located within the lower endof the hollow portion 7. A spring 20 normally urges the spindle l0downwardly so that the underface of the enlarged portion 15 bearsagainst the upper face of bearing 18. As shown, the lower end of thespring 20 is disposed within an annular aperture or cylindrical bore 20aformed in the top of the enlarged portion 15. The upper end of thespring 20 is seated against an annular spring retainer 20b which issuitably fixed, such as, by a cotter pin, to the engine shaft 17. Theouter peripheral surface of the enlarged portion 15 is provided with aconically shaped cam groove 21. The cam groove 21 includes a helicalportion 211: which serpentines from top to bottom and merges with anannular circular portion 21b. The cam groove 21 is selectively engagedby a conical roller 22 rotatably mounted and suitably secured to one endof a cam follower rod 23 by a lock or retaining ring (notcharacterized). The cam follower rod 23 is disposed within a laterallyextending cylindrical sleeve 24 formed on the side and near the upperend of the tubulure 7. The sleeve 24 includes an outer enlarged centralhole and an inner reduced central hole which guides the follower rod 23.The outer open end of sleeve 24 is threaded to receive anaperturedhexangular cap nut 25 which operates as a guide for the other end of thecam follower rod 23. Located internally of the enlarged central hole ofsleeve 24 and surrounding the intermediate portion of rod 23 is abiasing spring 26 having one end engaging the inner surface of the capmember 25. The other end of spring 26 is seated against an annularretainer 27. In practice, the spring retainer is held in place on thecam follower 23 by means of a cotter pin which is fitted in hole 28.Thus, the cam follower rod 23 and roller 22 are normally urged inwardlytoward the cam groove 21 by spring 26. As shown in FIGS. 4 and 5, theouter end of the cam follower rod 23 is provided with upper and lowerflattened surfaces 28a and 28b. Thus, the upper and lower surfaces 28aand 28b form a guide for a slotted wedge type of actuating mechanism ordevice 30. In viewing FIGS. 4 and 5, it will be noted that the outer endof cam follower rod 23 cooperates with an elongated slot 29 formed bythe tines of the wedge member 30. The spring 26 ensures that the head23a of the rod 23 constantly engages the outer tapered surface of thewedge 30. The inner edges of the head 23a are slightly slanted from-backto front to correspond with the tapered surface of the wedge 30. Theouter tapered surface of the wedge 30 is providedwith a groove orindentation 30a into which the head 23a is normally seated when thewedge 30 is moved to the wide end, namely, to itsextreme forwardposition, as shown in FIG. 4. Movement of the wedge 30 is imparted by anoperating device or mechanism through means of a linkage formed by rods31 and 32 which are coupled together by an adjustable turnbuckle 33. Aguide member 34 is suitably secured to the top of the housing 2 andholds the rods and wedge in the appropriate alignment with the end offollower rod 23. A biasing spring 35 normally urges the wedge andlinkage arrangement rearward or to the left, as

shown in FIGS. 1 and 2. The biasing spring 35 is held in compressionbetween the guide member 34 and retaining washer 35a which is suitablyheld in place on rod 31. The free end of the rod 32 is pivotallyconnected by pin 36 to the intermediate portion of a foot pedal 37. Thelower end of the foot pedal 37 is connected to a tripping device,suchas, pivotal member or kick flap 38. The kick flap 38 is pivotallymounted by a pair of L-shaped brakcets 39 and 40, each of which isbolted to the back end of the skirt portion 2b of the housing 2.Preferably, the brackets 39 and 40 maintain the flap 38 sufficientlyrearward of the mower housing so that the toes of an operator will notreach the tip of the rotary blade prior to the operators skin engagingthe flap. Thus, the flap, pedal, linkage and wedge member move as aunitary structure to control the position of the cam follower and, inturn, the position of the spindle and blade.

Generally during mowing operations, the blade 6 will occupy its lowergrass cutting position as shown in FIGS. 1 and 5.- Thus, the weight ofthe blade 6 and spindle 10 and the force fo the spring 20 will cause theblade lifting mechanism to assume a position as shown in FIG. 5. Underthis condition the cam follower is withdrawn and is held in itsdisengaging position by the thick edge or end of the wedge 30. That is,the head 23a of the cam follower rod 23 is resting in groove 30a so thatthe biasing force of the spring 26 is unable to move the cam followerroller 22 into engagement with the cam groove 21. Further, it will beappreciated that the engagement between head 23a and groove 30a resiststhe biasing efforts of spring 35 so that linkage will remain in theposition as shown in FIGS. 1 and 2.

Let us assume that the operator continues cutting grass and that heobserves a mound, a rock, or tree stump in his path of travel. Undersuch a circumstance the operator simply kicks or moves the flap member38 forward. The forward movement of flap 38 causes counterclockwiserotation of the foot pedal 37. The rotational movement of the foot pedal37 causes the linkage to shift toward rearward or to the left as shownin FIGS. 1 and 2. The initial shifting of the linkage separates the head23a from the groove 30a so that the spring 35 quickly moves the wedge 30rearward, namely, to the left as viewed in FIGS. 1 and 2. The thin edgeof the wedge 30 now allows the spring 26 to quickly move the roller 22into engagement with the upper end of helical portion 21a of the conicalcam groove 21. The conical roller 22 rapidly follows the serpentinegroove 21a and inhalf a revolution, or less, the roller 22 is riding inannular groove 21b. Thus, the rotating blade is quickly lifted from itslower grass cutting position to its upper position substantially againstthe undersurface of the housing 2 and within the area defined by rim 2c.Hence, as the mower passes over the obstruction no damage willresult tothe blade or to the lawn mower itself and no danger from flying objectswill arise to the operator or other individuals in the area. The roller22 will continue to follow the annular groove 21a and will maintain therotating blade in its upper position so long as no action is taken onthe part of the operator. When the dangerous c ondition no longerexists, the operator simply needs to step on and push the reset footpedal 37 forward. Such action causes the flap 38 to move in a clockwisedirection and again assume a position as shown in FIGS. 1 and 2. Theoushing of the pedal 37 also causes the linkage and in turn the wedge 30to move forward to a point where head 23a again engages groove 30a.Thus, the thick edge withdraws the cam follower rod 23 and roller 22from the lower annular cam groove 21b. The with-.

drawal of the roller 22 causes the blade6 and spindle 10 to drop undertheir own weight and with the assistance of spring so that the bladeagain assumes its lower grass cutting position. Thus, the-cutting blade6 is quickly and safely lifted out of possible contact with anobstruction and is subsequently easily returned to its grass cuttingposition when the dangerous condition no longer exists. It will beappreciated that there is little, if any, inconvenience to the operatorsince the blade does not stop rotating and the engine does not stoprunning.

Substantially, the same type of action or operation takes place when anoperators foot accidentally slides toward the housing on an embankmentor on wet grass, or when the operator inadvertently pulls the lawn mowerover his foot. As soon as the operators foot engages or touches the flap38, the blade 6 is quickly lifted up substantially against the undersideof the housing 2 and into the circular recess formed by the rim 2c. Therim 2c lessens the chances of severe injury to an operators foot sincethe ends and tips of the cutting blade are not exposed. In practice, itis desirable to let the blade be lifted to within a fraction of an inch,preferably about one eighth inch or so from the underside of the housing2 in order to maximize the amount of protection to the operator.

It has been found that the blade lifting mechanism also assists inpreventing damage to the mower when an unseen obstruction isinadvertently passed over. When a mound or a rock or the like iscontacted by the blade, an upward force is imparted to the blade so thatthe spindle l0 raises slightly and moves over the obstruction. That is,the spring 20 allows the rotating blade 6 and spindle 10 to moveupwardly due to the vertical component of the kinetic energy uponimpact, and thus little, if any, damage will result to the mower and theoperator and individuals in the area are in less danger of being hit byprojected objects.

Further, less danger and difficulty is encountered in starting the lawnmower, particularly in high grass. Prior to attempting to start theengine, the operator may simply kick the depending flap 38 so that thewedge moves to its thin edge. Now the wedge permits the cam follower androller 22 to enter the helical cam groove 21a upon the initialrevolution of theengine 5. Thus, the conical roller 22 follows thehelical groove 21a and raises the blade 6 to its uppermost position.With a raised blade the operator is obviously less likely of beinginjured, and the blade is normally out of contact with the high grass sothat easier starting results. After starting, the blade may be moved toits lower grass cutting position by simply standing on the reset footpedal 37. Thus, the operating mechanism controls the blade actuatingmechanism to selectively raise and lower. the grass cutting blade asdesired.

It will be appreciated that each time the cutting blade is moved to itsraised or upper'position any debris, such as, grass clippings and thelike, logged or attached to the underhousing is swept away by the highspeed cutting blade. Thus, the operator may periodically and preferablyprior to storage raise the blade for cleaning the underside of thehousing 2. The cleaning operation of the blade not only facilitates thecutting of the grass by continually providing an unimpeded path to thedischarge chute but also provides a convenient method of removing anyremanent grass clippings after each usage of the mower.

. It will be understood that variouschanges, modifications andalterations may be made to the presently described-arrangement withoutdeparting from the spirit and scope of our invention. For example, thetubulure 7 may be a completely separate member which can be bolted tothe top of housing 2 so that existing lawn mowers may be equipped withthe presently described blade lifting arrangement. In many existing lawnmowers a key and slot are employed for preventing relative rotationalmovement between the blade and motor output shaft and, therefore, it isapparent that the central bore of the enlarged portion 15 may be simplyprovided with a long slot or keyway for accommodating a key rather thanbeing splined as shown. Likewise, the central bore may be designed tocorrespond with other shapes of shafts and coupling arrangementspresently employed by the industry. 1

In addition, it is apprent that the underside of the housing should becontoured to the shape of the blade and the type of coupling employed sothat it may be raised as close as possible to the underside'of thehousing to maximize the protective cleaning and starting qualitiesderived from our invention.

Further, it is understood that other mechanical means may be employedfor lifting the blade, for actuating the blade lifter and for operatingthe actuator.

It is further understood that our invention is not limited to usage forhand-pushed or self-propelled walking mowers but also may be utilized onridingtypes of rotary lawn mowers.

Therefore, the details herein shown and described have been given onlyfor clarity purposes, and the breadth and scope of our invention is onlylimited by the claims annexed hereto.

Having thus described our invention, what we claim l. A safety mechanismfor a rotary type of motor driven lawn mower, comprising, a movablespindle housed within a tubulure carried by the housing of the lawnmower, a cutting blade attached to one end of said movable spindle andan output shaft of the motor of the lawn motor drivingly coupled to theother end of the movable spindle, a cam groove formed on the peripheralsurface of the other end of said movable spindle, a movable cam followermounted in a sleeve member carried by said tubulure, a wedge membernormally having its thick end in engagement with said cam follower, anda pivotal kick member mounted behind the housing of the lawn mower andlinked to said wedge member so that pivotal movement of said kick membercauses said wedge member to move its thin edge into engagement with saidcam follower whereby the cam follower is permitted to become engagedwith said cam groove which thereby causes the movable spindle to belifted upward so that the cutting blade is raised substantially adjacentthe underside of the housing of the lawn mower.

2. A safety mechanism for a rotary type of motor driven lawn mower asdefined in claim 1, wherein said cam groove includes a helical grooveextending from the top of said other end of said movable spindle andterminating into an annular groove formed on the bottom of said movablespindle.

3. A safety mechanism for a rotary type of motor driven lawn mower asdefined in claim 1, wherein said wedge member includes a slot whichaccommodates one end of said cam follower.

4. A safety mechanism for a rotary type of motor driven lawn mower asdefined in claim 1, wherein a reset foot pedal is coupled to said kickmember for moving said wedge member to its thick edge so that said camfollower is disengaged from said cam, thereby allowing said movablespindle to fall and causing said cutting blade to assume a grass cuttingposition.

5. A safety mechanism for a rotary type of motor driven lawn mower asdefined in claim 1, wherein said cam follower includes a conical rollerfor engaging said cam groove.

6. A safety mechanism for a rotary type of motor driven lawn mower asdefined in'claim 1, wherein a compression spring is disposed within saidtubulure and noramlly urges said cutting blade to a grass cuttingposition.

7. A safety mechanism for a rotary type of motor driven lawn mower asdefined in claim 3, wherein an indentation is formed on the thick edgeof said wedge member for holding said one end of said cam follower.

8. A lawn mower comprising, a skirted housing, a power motor mounted onsaid skirted housing, a rotary cutting blade driven by said power motor,and a safety mechanism including a foot operated device, an actuatingdevice and a blade lifting assembly, said blade lifting assemblysupported by said skirted housing, said foot operated device movablymounted to said skirted housing, said actuating device connected betweensaid foot operated device and said blade lifting assembly, and saidblade lifting assembly including a first means and a second meansoperatively associated to said cutting blade, said actuating deviceincluding a third means cooperatively engaged with said second means forshifting said second means into engagement with a first means forraising said rotary cuttingblade and for shifting said second means outof engagement with said first means for lowering said rotary cuttingblade.

9. A lawn mower as defined in claim 8, wherein a linkage is coupled tosaid third means for moving said. third means between a first and asecond position.

10. A lawn mower as defined in claim 8, wherein said blade liftingassembly includes a spring which'urges said rotary cutting blade to alower grass cutting position.

11. A lawn mower as defined in claim 8, wherein an annular rim is formedon the underside of said skirted housing.

12. A lawn mower comprising, a skirted housing, a motor mounted on saidskirted housing, a cutting blade powered by said motor, a safetymechanism including a foot operated device, an actuating device and ablade lifting assembly, said blade lifting assembly carried by saidskirted housing, said foot operated device mounted to the rear of saidskirted housing, said blade lifting assembly including a first and asecond means operatively coupled with said cutting blade, said actuatingdevice including a third means cooperatively engaged with said secondmeans, and a linkage operatively connected to said third means formoving said third means and causing said first and said second means toraise said cutting blade substantially against the underside of saidskirted housing.

1. A safety mechanism for a rotary type of motor driven lawn mower,comprising, a movable spindle housed within a tubulure carried by thehousing of the lawn mower, a cutting blade attached to one end of saidmovable spindle and an output shaft of the motor of the lawn motordrivingly coupled to the other end of the movable spindle, a cam grooveformed on the peripheral surface of the other end of said movablespindle, a movable cam follower mounted in a sleeve member carried bysaid tubulure, a wedge member normally having its thick end inengagement with said cam follower, and a pivotal kick member mountedbehind the housing of the lawn mower and linked to said wedge member sothat pivotal movement of said kick member causes said wedge member tomove its thin edge into engagement with said cam follower whereby thecam follower is permitted to become engaged with said cam groove whichthereby causes the movable spindle to be lifted upward so that thecutting blade is raised substantially adjacent the underside of thehousing of the lawn mower.
 2. A safety mechanism for a rotary type ofmotor driven lawn mower as defined in claim 1, wherein said cam grooveincludes a helical groove extending from the top of said other end ofsaid movable spindle and terminating into an annular groove formed onthe bottom of said movable spindle.
 3. A safety mechanism for a rotarytype oF motor driven lawn mower as defined in claim 1, wherein saidwedge member includes a slot which accommodates one end of said camfollower.
 4. A safety mechanism for a rotary type of motor driven lawnmower as defined in claim 1, wherein a reset foot pedal is coupled tosaid kick member for moving said wedge member to its thick edge so thatsaid cam follower is disengaged from said cam, thereby allowing saidmovable spindle to fall and causing said cutting blade to assume a grasscutting position.
 5. A safety mechanism for a rotary type of motordriven lawn mower as defined in claim 1, wherein said cam followerincludes a conical roller for engaging said cam groove.
 6. A safetymechanism for a rotary type of motor driven lawn mower as defined inclaim 1, wherein a compression spring is disposed within said tubulureand noramlly urges said cutting blade to a grass cutting position.
 7. Asafety mechanism for a rotary type of motor driven lawn mower as definedin claim 3, wherein an indentation is formed on the thick edge of saidwedge member for holding said one end of said cam follower.
 8. A lawnmower comprising, a skirted housing, a power motor mounted on saidskirted housing, a rotary cutting blade driven by said power motor, anda safety mechanism including a foot operated device, an actuating deviceand a blade lifting assembly, said blade lifting assembly supported bysaid skirted housing, said foot operated device movably mounted to saidskirted housing, said actuating device connected between said footoperated device and said blade lifting assembly, and said blade liftingassembly including a first means and a second means operativelyassociated to said cutting blade, said actuating device including athird means cooperatively engaged with said second means for shiftingsaid second means into engagement with a first means for raising saidrotary cutting blade and for shifting said second means out ofengagement with said first means for lowering said rotary cutting blade.9. A lawn mower as defined in claim 8, wherein a linkage is coupled tosaid third means for moving said third means between a first and asecond position.
 10. A lawn mower as defined in claim 8, wherein saidblade lifting assembly includes a spring which urges said rotary cuttingblade to a lower grass cutting position.
 11. A lawn mower as defined inclaim 8, wherein an annular rim is formed on the underside of saidskirted housing.
 12. A lawn mower comprising, a skirted housing, a motormounted on said skirted housing, a cutting blade powered by said motor,a safety mechanism including a foot operated device, an actuating deviceand a blade lifting assembly, said blade lifting assembly carried bysaid skirted housing, said foot operated device mounted to the rear ofsaid skirted housing, said blade lifting assembly including a first anda second means operatively coupled with said cutting blade, saidactuating device including a third means cooperatively engaged with saidsecond means, and a linkage operatively connected to said third meansfor moving said third means and causing said first and said second meansto raise said cutting blade substantially against the underside of saidskirted housing.